Effect Of Modifiers On The Properties Of Magnesium Oxychloride Inorganic Plywood

In this study,light burned magnesium oxide,magnesium chloride and self-made catalysts in the laboratory are used as raw materials to prepare magnesium oxychloride raw adhesive according to specific process procedures.On this basis,different amounts of perlite,calcium silicate,aluminum tripolyphosphate and their composite modifiers are added as modifiers,mixed and stirred evenly to make magnesium oxide adhesive,and evenly coated on poplar veneer after cold pressing to make plywood.By changing the amount of modifier added,combined with crystal phase composition,crystal morphology analysis,etc.,the effects of different amounts of modifiers and modifiers on the physical and mechanical properties,water resistance,and flame retardancy of magnesium oxychloride inorganic adhesive were explored.The feasibility of modifying magnesium oxychloride inorganic adhesive with perlite,calcium silicate,aluminum tripolyphosphate and their composite modifiers was investigated.The main conclusions of this study are as follows:(1)When the addition of perlite is 0.5%,the dip stripping length of the prepared plywood is the smallest,the modified plywood has better water resistance,and the internal bonding strength is not significantly reduced;When the addition of perlite was 1.5%,the static bending strength,elastic modulus,end nail holding force and side nail holding force of plywood were increased to 56.1 MPa,7178.4 MPa,1863.41 N and 1521.31 N,respectively,and reached the maximum;When the addition of perlite was 2.5%,the best flame retardancy of plywood was 668 s.(2)When the amount of calcium silicate added is 10%,the internal bonding strength of the prepared plywood reaches its maximum,which is 1.009 MPa;The prepared plywood has the smallest soaking peeling length,the lowest 24-hour water absorption rate,and the modified plywood has better water resistance;When the amount of calcium silicate added is 8%,the static bending strength,elastic modulus,end face nail grip force,and side nail grip force of the prepared plywood are increased to 65.4MPa,6372 MPa,1949.3 N,and 1356.7 N,respectively,reaching their maximum values;When the amount of calcium silicate added is 4%,the optimal flame retardant performance of the prepared plywood is 650 seconds.Compared with the absence of calcium silicate,the flame retardant time of the plywood is extended by 80 seconds.(3)When the amount of aluminum tripolyphosphate added is 4%,the internal bonding strength,static bending strength,elastic modulus,end grip force,and side grip force of the prepared plywood are increased to 0.783 MPa,70.8 MPa,8513.9 MPa,2122.76 N,and 1255.4 N,respectively.At the same time,the flame retardant performance of the modified plywood is improved to 650 s.Compared with the unmodified plywood,the flame retardant time of the plywood is extended by 80 s,reaching the maximum.(4)Compared with the absence of modifiers,the addition of composite modifiers can effectively improve the internal bonding strength of plywood.When the modifier is calcium silicate composite aluminum tripolyphosphate,the mechanical properties and water resistance of the modified plywood are better.The internal bonding strength,static bending strength,elastic modulus,end face nail grip force,and side nail grip force of the prepared plywood are increased to 0.975 MPa,69.5 MPa,8012.7 MPa,2215 N,and 1380 N,respectively,reaching their maximum values;When the composite modifier is perlite composite aluminum tripolyphosphate group,the best flame retardant performance of the plywood is 879 s.Compared with the unmodified plywood,the flame retardant time of the plywood is prolonged by 309 s.In addition,the plywood surface made by adding perlite,calcium silicate,aluminum tripolyphosphate and their composite modifiers has no obvious halogenation return and efflorescence.